One call with two employees who were traders. Discussed my experience and then IMC's directions of expansion. Did not do any specific problem solving or algorithms questions but I assume eventually would have had those interviews.
30 min HR screen, resume explanation background and IMC culture fit check. Mostly just behavior questions and a very simple brain teaser (takes about 2 min to solve). Also asked why trading
The first round hr call is a combination of both tech questions and behavioral questions such as why IMC and experience, also asked about whether have other offers and decisions deadline. Takes 30 min in all.